Publications

2026

1. BMVC

   

   M3T: Discrete Multi-Modal Motion Tokens for Sign Language Production

   Alexandre Symeonidis-Herzig, Jianhe Low, Ozge Mercanoglu Sincan, and 1 more author

   arXiv preprint arXiv:2603.23617, Nov 2026

   Abs arXiv Bib PDF Code Website

   

   Sign language production requires more than hand motion generation. Non-manual features, including mouthings, eyebrow raises, gaze, and head movements, are grammatically obligatory and cannot be recovered from manual articulators alone. Existing 3D production systems face two barriers to integrating them: the standard body model provides a facial space too low-dimensional to encode these articulations, and when richer representations are adopted, standard discrete tokenization suffers from codebook collapse, leaving most of the expression space unreachable. We propose SMPL-FX, which couples FLAME’s rich expression space with the SMPL-X body, and tokenize the resulting representation with modality-specific Finite Scalar Quantization VAEs for body, hands, and face. M3T is an autoregressive transformer trained on this multi-modal motion vocabulary, with an auxiliary translation objective that encourages semantically grounded embeddings. Across three standard benchmarks (How2Sign, CSL-Daily, Phoenix14T) M3T achieves state-of-the-art sign language production quality, and on NMFs-CSL, where signs are distinguishable only by non-manual features, reaches 58.3% accuracy against 49.0% for the strongest comparable pose baseline.

   @article{symeonidisherzig2026m3t,
     title = {M3T: Discrete Multi-Modal Motion Tokens for Sign Language Production},
     author = {Symeonidis-Herzig, Alexandre and Low, Jianhe and Mercanoglu Sincan, Ozge and Bowden, Richard},
     journal = {arXiv preprint arXiv:2603.23617},
     month = nov,
     year = {2026},
   }

2. ECCV

   

   SignSparK: Efficient Multilingual Sign Language Production via Sparse Keyframe Learning

   Jianhe Low, Alexandre Symeonidis-Herzig, Maksym Ivashechkin, and 2 more authors

   In European Conference on Computer Vision (ECCV), Sep 2026

   Abs DOI arXiv Bib PDF Code Website

   

   Sign Language Production (SLP) faces a fundamental trade-off: direct text-to-pose models suffer from regression-to-the-mean effects, while dictionary-retrieval methods produce disjointed transitions. To resolve this, we propose a novel training paradigm that leverages sparse keyframes to capture the underlying kinematic distribution of human signing. By generating dense motion from discrete anchors, our approach mitigates regression-to-the-mean while ensuring fluid articulation. To achieve this at scale, we introduce FAST, an ultra-efficient sign segmentation model that automatically mines precise temporal boundaries. We then present SignSparK, a Conditional Flow Matching (CFM) framework that utilizes these temporal anchors to synthesize 3D signing sequences. This keyframe-driven formulation also unlocks Keyframe-to-Pose (KF2P) generation, making precise spatiotemporal editing of signing sequences possible. Furthermore, SignSparK scales across four distinct sign languages, constituting the largest multilingual SLP framework to date, and integrates 3D Gaussian Splatting for photorealistic rendering. Extensive evaluations demonstrate that SignSparK achieves state-of-the-art across diverse SLP tasks and multilingual benchmarks. Our code is available at https://github.com/JianHe0628/SignSparK.

   @inproceedings{low2026signspark,
     title = {SignSparK: Efficient Multilingual Sign Language Production via Sparse Keyframe Learning},
     author = {Low, Jianhe and Symeonidis-Herzig, Alexandre and Ivashechkin, Maksym and Mercanoglu Sincan, Ozge and Bowden, Richard},
     booktitle = {European Conference on Computer Vision (ECCV)},
     series = {Lecture Notes in Computer Science},
     volume = {17005},
     pages = {648--670},
     publisher = {Springer},
     doi = {10.1007/978-3-032-37369-4_35},
     month = sep,
     year = {2026},
   }

2025

1. ICCVW

   

   VisualSpeaker: Visually-Guided 3D Avatar Lip Synthesis

   Alexandre Symeonidis-Herzig, Ozge Mercanoglu Sincan, and Richard Bowden

   In Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV) Workshops, Oct 2025

   Abs arXiv Bib HTML PDF Website

   

   Realistic, high-fidelity 3D facial animations are crucial for expressive avatar systems in human-computer interaction and accessibility. Although prior methods show promising quality, their reliance on the mesh domain limits their ability to fully leverage the rapid visual innovations seen in 2D computer vision and graphics. We propose VisualSpeaker, a novel method that bridges this gap using photorealistic differentiable rendering, supervised by visual speech recognition, for improved 3D facial animation. Our contribution is a perceptual lip-reading loss, derived by passing photorealistic 3D Gaussian Splatting avatar renders through a pre-trained Visual Automatic Speech Recognition model during training. Evaluation on the MEAD dataset demonstrates that VisualSpeaker improves both the standard Lip Vertex Error metric by 56.1% and the perceptual quality of the generated animations, while retaining the controllability of mesh-driven animation. This perceptual focus naturally supports accurate mouthings, essential cues that disambiguate similar manual signs in sign language avatars.

   @inproceedings{symeonidis2025visualspeaker,
     title = {VisualSpeaker: Visually-Guided 3D Avatar Lip Synthesis},
     author = {Symeonidis-Herzig, Alexandre and Mercanoglu Sincan, Ozge and Bowden, Richard},
     booktitle = {Proceedings of the IEEE/CVF International Conference on Computer Vision (ICCV) Workshops},
     pages = {6666--6675},
     month = oct,
     year = {2025},
   }